Many solid points. I beleive pricing has reached a tipping point to buy full season tickets. Often the season ticket holders will use their network to sell individual games they will not attend (or simply give away). Now that season tickets are becoming too expensive for most, those secondary users are removed and will not use the secondary market.
Ticketmaster is a problem. When they take a cut from both the seller and buyer, it makes prices less appealing.
another important point. Used to get tickets to PSU games through the years from friends and friends of friends and never paid much more than $25-$50. Was pretty common on gameday to find tickets being sold for $10 or $20 for people just holding them up and wanting something for them. Basically the face value of the ticket, many times penny on the dollar for 'bad' games. Now with the seat licenses and ticketmaster nearly impossible to find tickets 'cheap' like you used to.